Enhancing Men’s Awareness of Testicular Diseases (E-MAT) using virtual reality: A randomised pilot feasibility study and mixed method process evaluation

Introduction Testicular cancer is among the most common malignancies in men under the age of 50 years. Most testicular symptoms are linked to benign diseases. Men’s awareness of testicular diseases and testicular self-examination behaviours are suboptimal. In this pilot feasibility study and process evaluation we examine the feasibility of conducting a future definitive randomised controlled trial (RCT) to test the effect of the Enhancing Men’s Awareness of Testicular Diseases using Virtual Reality intervention (E-MATVR) compared to the Enhancing Men’s Awareness of Testicular Diseases using Electric information control (E-MATE). The study protocol is registered on ClinicalTrials.gov (NCT05146466). Methods Male athletes, engaged in Gaelic games, and aged 18 to 50 years were included. Recruitment was via FacebookTM, XTM (formerly TwitterTM), and posters. Participants were individually randomised to either E-MATVR or E-MATE. Data were collected at baseline (T0), immediately post-test (T1), and three months post-test (T2) using surveys. Qualitative interviews were conducted with participants and researchers. Results Data were collected from 74 participants. Of those, 66 were retained. All E-MATVR participants and most E-MATE participants (n = 33, 89.2%) agreed/strongly agreed that the device was easy to use and that they were engaged to learn by the device. Most E-MATVR participants (n = 34, 91.9%) and all E-MATE participants agreed/strongly agreed that the time it took them to complete the intervention was reasonable. All 74 participants were extremely satisfied/somewhat satisfied with their overall participation in the study. E-MATVR was described as interactive, easy, fun, and close to real life. Initial difficulty using VR equipment, nausea, and technical issues were identified as challenges to engaging with E-MATVR. Recommendations were made to make VR more accessible, shorten the survey, and incorporate more interactivity. Across all participants, mean testicular knowledge scores (range 0–1) increased from 0.4 (SD 0.2) at T0 to 0.8 (SD 0.2) at T1. At T2, overall mean scores for participants were 0.7 (SD 0.2). Mean knowledge scores did not differ by trial arm at any timepoint. At T2, all E-MATVR participants and 29/32 E-MATE participants (90.6%) reported purposefully examining their testes within the past three months. Conclusion Findings are promising, highlighting the feasibility of using VR to promote young athletes’ awareness of testicular diseases. Considering the strengths, limitations, and lessons learned from this study, some modifications are required prior to conducing an RCT. These include but are not limited to shortening survey questions, incorporating more interactivity and visual content, and targeting more heterogenous male-dominated environments.


Introduction
Testicular cancer is among the most common malignancies in men under the age of 50 years.Most testicular symptoms are linked to benign diseases.Men's awareness of testicular diseases and testicular self-examination behaviours are suboptimal.In this pilot feasibility study and process evaluation we examine the feasibility of conducting a future definitive randomised controlled trial (RCT) to test the effect of the Enhancing Men's Awareness of Testicular Diseases using Virtual Reality intervention (E-MAT VR ) compared to the Enhancing Men's Awareness of Testicular Diseases using Electric information control (E-MAT E ).The study protocol is registered on ClinicalTrials.gov(NCT05146466).

Methods
Male athletes, engaged in Gaelic games, and aged 18 to 50 years were included.Recruitment was via Facebook TM , X TM (formerly Twitter TM ), and posters.Participants were individually randomised to either E-MAT VR or E-MAT E .Data were collected at baseline (T0),

Introduction
Testicular cancer is one of the most common malignancies in men under 50 years of age [1].The incidence of testicular cancer has doubled over the last four decades [2].In Ireland, where our study was conducted, 176 men develop testicular cancer (2.4% increase per year) and 7 men die from it each year, with 91% of cases and 75% of deaths occurring in men younger than 50 years [3].
Histopathology reports of 215 orchidectomies (i.e., surgical removal of the affected testis) performed between 1975-1985 and 2007-2012 found that tumour size was reduced significantly [4].This was attributed to raising testicular cancer awareness in the United Kingdom (UK) [4].While orchidectomy remains the primary curative treatment for testicular cancer, other treatments such as radiotherapy and chemotherapy are administered depending on tumour type and stage.Watchful surveillance using clinical examination and ultrasound can be used for early-stage testicular cancer, particularly among patients who wish to postpone testicular cancer treatment for paternity purposes [5].However, it was found that clinical examination and ultrasound are not accurate enough to include patients in surveillance protocols [6], thus increasing the risk of disease progression [5].
A unilateral painless mass is the most common symptom of testicular cancer and, in 80% of cases, is discovered accidentally by men [7,8].Most testicular lumps, however, are benign caused by diseases such as epididymo-orchitis (i.e., infection in the epididymis and/or the testis) [9], and varicocele (i.e., dilation of the pampiniform venous plexus) [10].Other testicular diseases include testicular torsion (i.e., twisting of the testis) [11], which often causes severe scrotal pain and can lead to necrosis [11].Testicular torsion requires aggressive management in men presenting with testicular pain that has been ongoing for many hours, even 24 hours or more from the onset of ischemia [11].
Raising awareness and promoting testicular self-examination and early help-seeking can help detect testicular diseases early, reduce long-term treatment costs, and improve health outcomes.Experiencing testicular symptoms, however, does not necessarily mean that men would seek help.In the past, we found that barriers to help-seeking for symptoms of testicular disease among men include lack of awareness, embarrassment, fear of a cancer diagnosis, and symptom misappraisal [12].In addition, in our systematic reviews (n = 6), we found men's awareness of testicular diseases, intentions to seek help for symptoms of concern, and behaviours in terms of performing testicular self-examination were all suboptimal [13][14][15][16][17].
Athletes involved in contact sports have an increased risk of testicular trauma and subsequent diseases.A survey of 731 athletes in the USA found that the prevalence of testicular injuries in field games was 48.5% [18].Hurling, one of the oldest and fastest field games in Ireland, is played with a ball made from cork (i.e., sliotar) covered in leather and struck with a wooden stick (i.e., hurley).When struck, the sliotar can reach a speed of 160 km/h which poses significant injury risk either by the sliotar or the hurley [19].A single-centre Irish study reported that, out of 70 patients presenting with penoscrotal injuries, 10 (14%) had injuries caused by blunt scrotal trauma whilst playing hurling [20].Of those, 9 (90%) had positive findings on ultrasonography, 3 (33%) required operation, and 1 (10%) underwent an orchidectomy [20].
The use of virtual reality (VR) in general [21], and in healthcare in particular [22] is on the rise.The evidence available to date to support the use of VR in men's health promotion is limited.We previously found that VR was user-friendly and acceptable for attracting younger men into research on testicular diseases [23].We also conducted a one-group pre-post pilot study where we delivered the Enhancing Men's Awareness of Testicular Diseases using a Virtual Reality (E-MAT VR ) intervention to help raise men's awareness of testicular diseases, promote testicular self-examination, and encourage early help-seeking [24].Findings were promising; however, a major limitation was the lack of a control group.Therefore, we were unable to determine whether the changes in outcomes were caused by the intervention, the use of repeated measures, or unforeseeable factors [24].Moreover, to the best of our knowledge, no trials have investigated the use of VR in men's health promotion and no studies have evaluated the process of delivering VR in a trial from the perspective of participants and researchers.
Pilot feasibility studies and process evaluations are important steps in the Medical Research Council (MRC) framework for developing and evaluating complex interventions [25].In their conceptual framework, Eldridge et al. [26] emphasised the importance of pilot feasibility studies in preparation for randomised controlled trials (RCTs).Such studies ask whether something can be done, should researchers proceed with it, and if so, how.They also assist with decision-making in preparation for a future RCT, including decisions around randomisation and recruitment [26].
Trials with no process evaluations are rarely adequate for complex intervention research [25].Process evaluations combining qualitative and quantitative methods help answer questions around fidelity, quality of implementation, mechanisms of change, and context.Such evaluations are key to determining why an intervention fails, why it works, and how it can be optimised [25].
In the context of our study, the conduct of a pilot feasibility study with embedded mixedmethod process evaluation helped us explore uncertainties that need to be addressed prior to conducting a future RCT.These include: recruitment; randomisation; the use of a comparator; participant retention; time taken to deliver the intervention; practicality of delivering the intervention; as well as intervention feasibility, usability, and adherence.

Aim
The aim of our study was to pilot the effect of the E-MAT VR intervention compared to the Enhancing Men's Awareness of Testicular Diseases using Electronic information control (E-MAT E ) among male athletes and coaches engaged in indigenous Gaelic games.A mixed method process evaluation was embedded in the pilot feasibility study to understand and mitigate potential sources of future intervention failure and explore participants' and researchers' experiences of E-MAT VR and E-MAT E .

Trial design
A two-arm parallel-group randomised (1:1) pilot feasibility study was conducted in line with Eldridge et al.'s [26] guidance and conceptual framework.The trial protocol is registered in ClinicalTrials.gov(Identifier: NCT05146466) [27] and is available in S1 File.There have been no deviations from the pilot feasibility study protocol.Reporting of the trial adhered to the Consolidated Standards of Reporting Trials (CONSORT) statement for pilot and feasibility trials [28] (S2 File).Participant enrolment, allocation, follow-up, and analyses are illustrated using the CONSORT flow diagram (Fig 1).
The embedded mixed method process evaluation applied a descriptive realist evaluation using MRC guidance on process evaluations of complex interventions [29].This involved exploring what works, for whom, and under what circumstances [30].In compliance with MRC guidance [29], a logic model adapted from the Kellogg Foundation Framework was used to summarise the inputs, activities, outputs, outcomes, and impact of the intervention (Fig 2).The evidence-based underlying assumptions were also described along with barriers and facilitators for implementation [13,15,16,20,23,24,31,32]. The protocol for the mixed method process evaluation is published elsewhere [33].There have been no deviations from the mixed method process evaluation protocol.

Participants
Eligibility criteria.Individuals eligible to participate in the study met the following criteria: (i) assigned male at birth; (ii) aged 18 to 50 years (i.e., age group at highest risk for testicular diseases); (iii) residing in the Republic of Ireland; and (iv) players and/or coaches in Gaelic Athletic Association (GAA) clubs.GAA is Ireland's largest international amateur sporting and cultural organization, with over 500,000 members in 2,200 clubs nationally [34].GAA is focused primarily on promoting indigenous Gaelic games and pastimes, which include the traditional Irish sports of hurling, camogie, Gaelic football, Gaelic handball, and rounders [34].Of note, given that the focus of our study was on process and feasibility rather than efficacy, individuals with a history of testicular disease were eligible for inclusion.
Individuals who were younger than 18 years or older than 50 years, not assigned male at birth, residing outside the Republic of Ireland, and not involved in GAA as either players or coaches were excluded.VR rarely causes motion sickness and the risk for seizures is negligible [35].However, for safety reasons, individuals with a history of seizures and/or motion sickness were excluded.The four researchers who delivered E-MAT VR and E-MAT E and collected data were also eligible to participate in the process evaluation to explore their experiences conducting the study.
Setting.GAA clubs are increasingly adopting "The Healthy Club" philosophy to improve the health of their members [32].Therefore, participation was primarily sought from geographically dispersed Healthy GAA clubs in the south of the Republic of Ireland.
An invitation letter was e-mailed on two occasions to the executive committee of each club.Clubs that responded to the e-mail and expressed their interest in participating were asked to advertise the study on their Facebook TM and X TM (formerly Twitter TM ) pages.Social media posts explained what the study involved and comprised a link that club members accessed to provide their contact details and register their interest in participating.Ten posters with a quick response (QR) code with the same link were displayed in each participating club.Each recruitment strategy (i.e., Facebook TM , X TM , and poster with QR code) was implemented over two weeks per club at random, for a total of six weeks [36].
Club members who registered their interest in participating were contacted by the researchers to assess their eligibility.Potential participants who were eligible were provided with an information leaflet explaining the study process and the risks and benefits from their participation and were given an opportunity to speak to a member of the research team if they had any questions or concerns.They were then asked to provide written informed consent in the presence of research personnel, and those who did were enrolled into the study.Participants were required to sign a second informed consent form if they wished to participate in qualitative interviews as part of the process evaluation.Researchers were also asked to provide written informed consent if they wished to be interviewed.
Procedures.Data were collected at baseline (T0), immediately post-test (T1), and three months post-test (T2) using the Castor EDC software, a secure clinical data management platform that enables researchers to easily capture and integrate data [37].Participants completed a baseline questionnaire (T0).They were then individually randomised to either trial arms.Immediately after exposure to E-MAT VR or E-MAT E , they completed a second questionnaire (T1).Four research personnel collected T0 and T1 data in-person in participants' respective GAA clubs, usually before a training session.
Three months post-test (T2), participants received a link by e-mail to complete the third and final questionnaire.Two subsequent reminders were sent, and non-respondents were considered lost to follow-up.Participants who completed T0, T1, and T2 questionnaires received a gift voucher as a token of appreciation.

Interventions
The study followed MRC guidance for developing and evaluating complex interventions [25].Participants randomised into the active arm of the study received E-MAT VR , which was developed between 2014 and 2018.E-MAT VR is underpinned by the Preconscious Awareness to Action Framework [38], and the concept "testicular awareness" [39].The development and usability testing of E-MAT VR is reported elsewhere [23,24].E-MAT VR is an educational intervention aimed at raising awareness of testicular diseases and promoting testicular self-examination.It is a bespoke computer software installed onto the latest VR technology and delivered using a wireless headset, handheld controllers, and built-in headphones with voiceover.E-MAT VR is an interactive serious gaming experience with three individual areas, representing three gaming levels.The intervention takes approximately 10 minutes to complete.A tutorial on how to use the VR headset and controllers is embedded within E-MAT VR .
The E-MAT VR intervention begins with a sequence of popping words as the voiceover reads them out.These include light-hearted synonyms for the testes (e.g., balls, nuts, and gonads).Of note, the words "nuts" and "balls" were used rather than "testes" and "testicles" to help engage participants with this intimate and sensitive topic [31].Participants were then transported to a virtual apartment with each room representing one game area.They were required to complete tasks in one area to move to the next area.
Area 1 is the shower, the ideal place to perform testicular self-examination.It involves a 3D space represented as an oversized shower with two walnuts floating in the centre.Participants were asked by the voiceover to move around the walnuts using the handheld controllers, while providing information about the normal size and shape of the testes.Three changes (i.e., lump, swelling, and pain [represented as flashing light]) then appeared consecutively.These were associated with humorous responses from the voiceover.The participant was required to find all three changes to move to the next area.
Area 2 is the bedroom.It involves using a 3D model of a testis.The spermatic cord, epididymis, and lump/tumour are represented in this model.In this area, the voiceover connects symptoms experienced in area 1 to testicular structures.For example, the spermatic cord glows to indicate testicular torsion and a purple lump appears, indicating a growth/lump.Participants were required to click on each of the three structures to move to the next and final area.
Area 3 is the kitchen living room.Here, key messages are reiterated by the voiceover using three objects: (i) a poster of a fingerprint to remind participants that their testes are unique, hence the importance of knowing what is normal for them; (ii) an infographic with the steps for testicular self-examination; and (iii) a first aid kit to prompt participants to seek help for symptoms and seek emergency/immediate medical attention for sudden and severe testicular pain.Participants were required to click on each of the three objects to hear the messages.Screenshots from the different areas within the E-MAT VR intervention are presented in Fig 3.
Participants in the control arm (E-MAT E ) received the same information as E-MAT VR but delivered as plain text in Portable Document Format (PDF), with screenshots from E-MAT VR similar to those in Fig 3 . E-MAT E participants were given up to 10 minutes to read the text and look at images using a tablet.

Outcomes
The full details of the instruments used to collect data in the pilot feasibility trial and process evaluation including how and when they were used are presented in Table 1.All instruments used in the pilot feasibility trial and most instruments used in the process evaluation were developed, validated, and pilot tested elsewhere [24,[40][41][42].No changes were made to these instruments in the current study.

Process evaluation outcomes
Participants who consented were interviewed individually either in-person immediately after T1 or later via telephone.The research team participated in a virtual focus group to glean their perspectives of delivering the intervention/control.A semi-structured interview guide was used for participants and researchers (S1 Table in S3 File).Interview guides were developed by four senior academics and researchers who have experience in qualitative research (MMS, MMC, MPD, JH).The interviews and focus group explored how E-MAT VR and E-MAT E were perceived by participants and researchers, if/why this varied, and how these perceptions affected intervention/control receptivity.The interviews and focus group also explored the mechanisms through which the intervention/control brought about changes in testicular awareness, which is crucial to understanding how the effects of the intervention/control occurred and how these effects might be replicated in the future [30].
Context which includes anything peripheral to the intervention/control that may influence its implementation, reach, or effects was measured using a survey.The interview and focus group topic guide explored in what context the intervention/control was effective or ineffective, and whether they might be transferrable to other contexts.The usability and satisfaction survey contained a checklist of items with three of those items examining the impact of context on the implementation of the intervention/control.This included determining whether the intervention/control was applicable to real life, men across a range of ages (18 to 50 years), and men from different ethnic backgrounds.
Fidelity checks were conducted to check if E-MAT VR and E-MAT E were delivered as intended.This involved having a researcher observe participants during testing and recording (tick box) pre-specified items (e.g., participants' behaviour, interest, and engagement) [43].The quality of delivery was also assessed during the fidelity checks.These checklists were purposefully developed for use in the current study.Checklist items were mapped onto the processes and contents of the E-MAT VR intervention and E-MAT E control.These checklists were pilot tested with four participants.Data from these participants were not included in the final analysis.No changes were made to these checklists following pilot testing.Data were collected on dose exposure, dose completeness, and dose satisfaction.The time taken to deliver E-MAT VR and E-MAT E and the units of intervention/control completed (dose completeness) were captured in minutes.Data were recorded automatically within and extracted from the VR headset for E-MAT VR participants.The time it took participants to complete E-MAT E in minutes was recorded manually by the observing researcher.Participants' satisfaction with the intervention/control, interactions with research staff (dose satisfaction), and extent to which participants were receptive to the intervention/control (dose exposure) were collected in the usability and satisfaction survey.
Reach refers to the proportion of the intended population that participated in the study measured by the number of participants within each arm [29].In our study, reach was determined by comparing the number of participants who consented to participate relevant to the number of GAA players and coaches who registered their interest in participating but did not.
Feasibility and satisfaction were measured using instruments which assessed usefulness, ease of use, and level of satisfaction with use of both E-MAT VR and E-MAT E [23,42].
Finally, four open-ended questions explored elements of the study that worked and did not work for participants, and any possible changes they would like to make [23,42].Process evaluation data including timing, difficulties experienced during E-MAT VR /E-MAT E , frequency of adverse events, and implementation problems were also collected by researchers during the study.Implementation problems identified during the trial were categorised as they arose, including the mechanisms by which the issues were addressed.Pilot efficacy outcomes.The primary efficacy outcomes were testicular knowledge and testicular self-examination behaviours.The testicular knowledge questionnaire measured participants' knowledge of the anatomy of the testes, common testicular symptoms and diseases, and testicular self-examination using 12 multiple choice questions [24].
At T0, three items explored whether participants performed testicular self-examination within the past year and month [24].They were also asked if a healthcare professional ever examined their testes.At T2, one item explored whether participants performed testicular selfexamination over the past three months (i.e., since exposure to the intervention/control).All item responses were dichotomous (Yes/No).
The secondary efficacy outcomes included testicular awareness, perceived risk of testicular diseases, help-seeking intentions, implementation intentions, and recommendation of testicular self-examination to others.The testicular awareness scale is a 5-point Likert scale that assessed participants' testicular awareness, that is their familiarity with their own testes, knowledge of what is normal and what is not normal, and ability to differentiate between what is normal and what is not normal [24,39].
Participants' perceived risk of testicular diseases was assessed using one item.The level of agreement for this item was measured on a 5-point Likert scale [24].
Participants' intentions to seek help for testicular symptoms were assessed using the General Help Seeking Questionnaire [24,40].Here, three items assessed participants' intentions to seek help for three different symptoms (i.e., testicular swelling, lumpiness, and pain) from various sources of help.
Implementation intentions "specify the when, where, and how of responses leading to goal attainment" (p.121) [41].The Implementation Intentions Scale comprised three items assessing participants' intentions to feel their own testes in the shower/bath at least once over the coming month and their intentions to advise at least one man to do the same [24].The level of agreement for each item was measured on a 5-point Likert scale.
One item assessed men's behaviours in relation to advising at least one man to feel their testes at T2.Item responses were dichotomous (Yes/No) [24].
A sociodemographic questionnaire was administered at T0.It comprised 11 items as follows: age; gender; nationality; marital status; name of GAA club; role in GAA club; highest level of education; current occupation; personal history of testicular disease(s); prior experience with VR; and where participants heard about the feasibility trial.Of note, the names of participating GAA clubs are not disclosed in this paper for confidentiality purposes.

Sample size
The goal of a pilot feasibility study is to identify problems that would impede the conduct of a larger, definitive RCT.There is no gold standard for sample size calculation in pilot feasibility studies and sample sizes as small as 10 and as large as 59 have been recommended [24].Julious [44], for example, suggested a sample size of 12 per arm, whereas Viechtbauer et al. [45] proposed a formula to calculate the sample size in pilot studies and reported that "if a problem exists with 5% probability in a potential study participant, the problem will almost certainly be identified (with 95% confidence) in a pilot study including 59 participants" (p.1375).Therefore, we set the sample size in our study at 59 [45].Allowing for a potential attrition rate of 25%, we aimed to recruit 74 participants.

Randomisation
For each participating GAA club, individual participants were randomised to one of the two trial arms (E-MAT VR or E-MAT E ) using the Castor EDC software.Allocation concealment was maintained using the Castor EDC software.Once participants had consented and their baseline assessment (T0) had been entered into the Castor EDC software, their allocation was given by automated e-mail.Randomisation and allocation concealment were conducted according to the standard operating procedures of the Statistics and Data Analysis Unit of the Health Research Board Clinical Research Facility, University College Cork, Ireland.
Given the differences between the two arms, participants were made aware of the arm they were randomised to once they were assigned to either E-MAT VR or E-MAT E. Outcome assessments were self-reported and returned to research staff with no information on allocation.The data analyst was also blinded to allocation until database lock and completion of the protocolspecified data analysis.

Statistical methods
Quantitative data analysis.Prior to analysis, data underwent extensive quality checking.Given the feasibility aims of the trial, analyses of participant outcomes were largely descriptive.However, we did estimate between-arm contrasts for the knowledge scores and the testicular self-examination behaviours on an intent-to-treat basis.For the former, we estimated the between-arm difference in mean scores using linear regression with adjustment for baseline scores; for the latter we estimated odds ratios using logistic regression.Resulting effect estimates were reported with 95% confidence interval (CI) and p-values.Missing data were addressed using complete case analysis, following from the small number of missing values.Because the pilot feasibility trial was not designed to return a high-powered test of the efficacy of the intervention, we report these results on a purely exploratory basis, and for the purposes of informing the design of a subsequent RCT.Simple between-arm tests for ordinal responses were conducted using Kruskal-Wallis rank sum tests.For multi-item scales, we evaluated the internal consistency of items using Cronbach's alpha [46], or the equivalent Kuder-Richardson 20 (KR-20) metric [47] when the items were binary.All reported p-values are based on twosided tests with statistical significance defined as p<0.05.
Analyses were conducted using R (v 4.2.0) and RStudio (2023.06.0 Build 421).All analysis steps, including cleaning or modifications to study database, were fully scripted and replicable.Upon completion, the study database was prepared according to the findability, accessibility, interoperability, and reusability (FAIR) data principles and made available along-side the analysis scripts via the Open Science Foundation (https://osf.io/m5wb7/).
Qualitative data analysis.Qualitative data from the interviews with participants and focus group with researchers were analysed using qualitative content analysis with pre-defined main categories reflective of the key constructs within the logic model, with an openness to emergent themes [48,49].All qualitative data were coded and analysed in NVivo.Similar codes were grouped to form sub-categories which were then collated under main categories.Qualitative data analysis was conducted by one author (MMC) and checked for accuracy by two authors (MPD, JH) to minimise errors and improve data credibility and confirmability [50].
Data from the four open-ended questions were analysed using quantitative content analysis which involved systematically categorising and recording textual material so that they can be analysed [51].

Process evaluation outcomes
Context.All participants in E-MAT VR and 97.3% (n = 36) of those in E-MAT E either agreed or strongly agreed that the intervention was applicable to men aged between 18 and 50 years.There were similar findings regarding applicability to those from different ethnic and cultural backgrounds; the majority of E-MAT VR (n = 33, 89.2%) and E-MAT E (n = 36, 97.3%) participants either agreed or strongly agreed.Thirty-six (97.3%) participants in both E-MAT VR and E-MAT E either agreed or strongly agreed that the intervention was close and applicable to real life (S2 Table in S3 File).
Fidelity.High quality of delivery was associated with both E-MAT VR and E-MAT E (fidelity score �80%).All participants in E-MAT VR received a safety briefing and an explanation on the use of the VR headset and controllers.All participants used the VR equipment and began the VR experience as instructed.Two participants in E-MAT VR (5.4%) ended the VR experience early.One due to nausea and one due to a technical problem in the VR headset.All E-MAT E participants could use the tablet (n = 37, 100%) and almost all E-MAT E participants appeared to read everything on the tablet (n = 35, 94.6%).
Dose and reach.Data on dose exposure were not available for seven participants in E-MAT VR and one participant in E-MAT E .The mean completion time was 9.45 minutes (range 7.15 to 12.31 minutes) for E-MAT VR and 4.07 minutes (range 1.50 to 7 minutes) for E-MAT E .As for reach, the target sample size of 74 participants was reached.
Usability and satisfaction.Most participants (67/74, 90.5%) either agreed or strongly agreed that the device was comfortable to use in both E-MAT VR (n = 34, 91.9%) and E-MAT E (n = 33, 89.2%).All participants in E-MAT VR agreed or strongly agreed that the device was easy to use and that they were engaged to learn by the device.While 33/37 E-MAT E participants (89.2%) agreed or strongly agreed with these statements.Similarly, 34/37 E-MAT VR participants (91.9%) either agreed or strongly agreed that the time it took to complete was reasonable and all E-MAT E participants agreed with this statement.All 74 participants either agreed or strongly agreed that the information provided by the device was clear (S2 Table in S3 File).All 74 participants were either extremely satisfied or somewhat satisfied with their experience of using the PDF reader on the tablet (E-MAT E ) or VR system (E-MAT VR ) to learn about testicular diseases.Similarly, all E-MAT VR participants and 36/37 E-MAT E participants (97.3%) were either extremely satisfied or somewhat satisfied with their overall experience of participating in the study (S3 Table in S3 File).
Responses were explored in greater depth during qualitative interviews with nine participants.As a result, seven main categories and 22 sub-categories were identified.The seven main categories were: Positive aspects of the study; positive aspects of E-MAT VR ; positive aspects of E-MAT E ; challenging aspects of E-MAT VR ; challenging aspects of E-MAT E ; motivation for participating; and recommendations for future research.The main categories, sub-categories, and codes are presented in Table 3.The letter "P" is used to designate participants hereafter.
Positive aspects of the study.Participants in both, E-MAT VR and E-MAT E described their experience of participating in the study as "enjoyable" (P2, P3, P9) "easy" (P2, P3, P4) and "informative" (P3).One participant seemed motivated to perform testicular self-examination following his participation in the study: "It brings it more to the front of your mind to do checks on yourself" (P8).
Challenging aspects of E-MAT VR .For some participants, navigating the VR environment proved challenging initially as the "controllers were a bit confusing at first" (P4).One participant reported "feeling slightly dizzy at the start" (P4).Fear of the unknown was also an initial concern voiced by one participant: "I felt a tiny bit anxious at the very beginning. ..because you don't know" (P5).A technical issue was reported by another participant: "It [E-MAT VR ] froze at the end" (P3).Challenging aspects of E-MAT E .Participants felt that E-MAT E "wasn't very interactive" (P2) or interactive only "to a certain degree" (P7).Some participants reported that E-MAT E had "too much text" (P8) and a "good bit of information" (P7).As a result, one participant reported information overload: "Hard to take it all in" (P7).
Motivation for participating.Some participants were motivated to participate in the study to "find out more about men's health" (P9), particularly in relation to testicular diseases, as described by one participant: "I didn't really have too much information on the disease, only a small bit there in secondary school" (P7).Others volunteered to participate because the study was "easy" (P6), "quick" (P8), "simple" (P9), and "wasn't time consuming" (P9).For many, the "50-euro voucher" (P6, P7, P8, P9) given to participants following completion of the third and final questionnaire at T2 incentivised them to participate.
Recommendations for future research.Participants made several recommendations to improve E-MAT VR and E-MAT E .Both, E-MAT VR and E-MAT E participants recommended making the VR game and tablet "more interactive" (P5, P8).Several E-MAT E participants advised including "videos" (P6, P7, P8) and "visual interaction" (P7).One participant recommended incorporating VR into secondary school and university curricula: "Maybe it's something that should be introduced in secondary schools, colleges, as part of a curriculum. ..to show it to older classrooms, older age groups in secondary schools" (P6).Others recommended using the tablet because it is "straightforward" (P8), "easy to follow" (P6), and "people are well used to using the device" (P7).
Focus group with researchers.Five main categories and 21 sub-categories were identified from the focus group with the four researchers who collected data.The five main categories were: Positive aspects of E-MAT VR ; challenges to engaging with E-MAT VR ; resources incurred; surveys at T0 and T1; and recommendations for future research.The main categories, sub-categories, and codes are presented in Table 4.The letter "R" is used to designate researchers hereafter.
Positive aspects of E-MAT VR .Three research personnel discussed the benefits of using VR in various contexts and settings (R1, R3, R4).One researcher discussed the benefits of using VR in education: "So yes across education, it could be provided in any context really" (R1), while another spoke about the value of using VR in other health contexts: "So I know as well you have a student working a breast cancer one. ..you can do anything with it technically" (R4).In addition, researchers discussed the "enjoyment" (R3) element of VR which made it a "fun way for them [participants] to learn" (R1).One researcher felt E-MAT VR was valuable for educating students prior to going on clinical placements: ". ..they [participants] get that sense of what it might be like before they go on placement. ..that experience and that practice beforehand-I think it could be really helpful" (R1).Another researcher felt that E-MAT VR served as a "humorous way to give the information" (R4) which might help "keep people interested" (R4) and educated about testicular diseases.In contrast to E-MAT E which was described by one researcher as "more boring" (R1), E-MAT VR was described as "more interesting and interactive" (R2).
Challenges to engaging with E-MAT VR .Information delivery proved challenging, as described by one researcher: "They [participants] are really just being told to point at something" (R4).Technical issues were also reported.These related to VR headsets: "Making sure the batteries didn't die on the VR because they were used back-to-back" (R1), poor graphics due to ill-fitting headset: "Even people with glasses.I think we had a situation where you know the screen went blurry for them" (R1), and researchers having to use their personal Facebook TM accounts to sign in: "The Oculus TM [VR headset brand] portal. ..that is kind of a bit of a tricky situation. ..when you can't make dummy Facebook TM accounts for it, you have to use personal Facebook TM accounts" (R2).Another challenge relating to E-MAT VR was the risk of nausea: "I think, maybe one or two people on the day. ..maybe one guy in particular got very nauseated from it" (R3).
Resources incurred.Researchers discussed the obstacles they encountered while conducting data collection, specifically in relation to lack of time and personnel available: "Trying to do fidelity checks at the same time while they were doing the interventions was actually a little bit tricky" (R1).Therefore, "allocating the time" (R1) for participants, ensuring there was "enough research members there" (R1), and having "more manpower. ..somebody doing the checks specifically" (R2) were highlighted as key during data collection.Another challenge related to recruiting participants, particularly among those who initially registered their interest in participating but did not respond to the invite to participate: "When they [participants] are confronted with the sort of the email to say 'oh thank you for signing can we organise something', that initial interest maybe drops off" (R2).Surveys at T0 and T1.Researchers felt that some survey questions at T0 and T1 were "similar" (R3, R4) and "overlapping" (R3).This led to confusion among some participants: "A few people did get a bit confused with the T1 questions. ..they thought they were answering the same thing again" (R4).Therefore, explaining briefly to participants that the questions are similar in the surveys was an important lesson learned: "Just mention that like these are going to be similar questions again you already answered. ..it takes a second to say it to them" (R4).In addition, the surveys did not capture "technical feedback" (R4) or information about the "usability of the software" (R4).However, one researcher noted that "putting extra [questions] would have been impossible" (R4) due to the length of the surveys at T0 and T1.
Recommendations for future research.Researchers recommended incorporating VR into education and learning by "bringing them [VR headsets] around to secondary schools. ..GAA clubs" (R4), and having a designated location "where people can learn in their own time" (R4) such as "[University] library. ..so if someone wants to spend time they can book that out and they have the headsets" (R4).Making VR accessible was also perceived as important, with one researcher discussing the need to "bring them [VR headsets] to the people. ..people aren't very likely to download them" (R4) so "it [E-MAT VR ] has to exist somewhere where people can go to it and. ..freely" (R4).Ensuring VR is accessible to everyone and not just GAA players was also discussed: "I would go for sports players in general. ..not just limited to GAA" (R4).Accommodating different levels of VR experiences among participants was also advised by researchers, particularly for "those who struggled with the VR" (R1) and needed "a longer tutorial" (R1) or an "extra bit of guidance of at the start" (R2).Going forward, one researcher recommended having "a process set in stone. ..to say that this is how we do it...and this is how we deal with people who aren't so used to VR" (R4).Another key recommendation by researchers was to have "more training" (R1, R4) for the use of Castor EDC software for data collection to help make the process "a little more. ..streamlined" (R2).Finally, one researcher suggested more "user testing" (R4) to help "find bugs" (R4) in E-MAT VR .Another researcher suggested "tweaking" (R3) the survey questions to get more "concise" (R3) and "insightful" (R3) answers.

Pilot efficacy outcomes
Across all participants, mean knowledge scores increased from 0.4 (SD 0.2) at baseline to 0.8 (SD 0.2) at T1.At T2, overall mean scores for participants were 0.7 (SD 0.2).However, the mean knowledge scores for E-MAT VR versus E-MAT E participants did not differ at any timepoint (Table 5).

Discussion
Fewer than 50% of trials meet their recruitment targets [52].The top reasons for recruitment failure and high attrition rates include overoptimistic recruitment targets, narrow eligibility criteria, lack of researcher engagement, lack of researcher training and experience in recruitment, insufficient funding, and high participant burden [53].This highlights the importance of conducting feasibility studies inclusive of process evaluations, hence our study.
We set our sample size at 59 [45].Bearing in mind a potential attrition rate of 25%, we recruited 74 participants within six months.Only 10.8% of participants were lost to follow up, yielding a final sample size of 66 participants.Successful recruitment and the low attrition rate can be attributed to several factors.These include but are not limited to: Having a dedicated budget for social media advertising/recruitment; involvement of two patient and public contributors in recruiting participants from their respective GAA clubs; developing a standard operating procedure to ensure the standardisation of data collection among the four researchers across all data collection sites; the trial being categorised as low risk; the use of innovative technology namely VR that is appealing to younger men; collecting data in GAA clubs taking into account participants' availability/preferences; contacting participants at T2 using their preferred contact method(s); sending automated reminders to participants to complete the third and final survey at T2 (i.e., an initial e-mail with two reminders); and giving participants who complete the final survey a gift voucher.
As for the instruments, completion was acceptable with little missing data.Primary and secondary efficacy outcomes improved regardless of study arm.This is encouraging, particularly in the context of educating hard-to-reach populations such as young and healthy men.Given that the aim of a feasibility study is to examine the feasibility of conducting a definitive RCT, estimated effects based on between-arm contrasts in outcomes are exploratory and aimed at informing the design of a future RCT [26].That said, with respect to knowledge scores, the observed data showed no benefit of E-MAT VR over E-MAT E .This is not unexpected in a small feasibility study.
The latest MRC framework for developing and evaluating complex interventions calls for researchers to consider six core elements relating to the process of implementation [25].These include how the intervention interacts with the context; how it is underpinned by programme theory; what are the diverse stakeholder perspectives; what are the key uncertainties; what is the potential for the intervention to be refined; and are there comparative resource and outcome consequences of the intervention [25].Findings from the embedded mixed method process evaluation indicate that participants were favourable towards the feasibility and application of the intervention/control. Furthermore, high levels of satisfaction with the quality, delivery, and experience were noted.Findings from the current study provide a framework of learning towards the effective implementation of a larger RCT.
Implementation science frameworks and logic models enunciate the importance of understanding the influence of context and external influencing factors in establishing the feasibility of implementing an intervention [54].These factors support implementation by mitigating certain factors of intervention failure.In the current study, recruitment was assisted by the availability and promotion of a small bursary, enthusiastic champions/patient and public collaborators, access through GAA clubs, and the novelty of the intervention.These inputs and activities resulted in high levels of engagement, follow-up, and satisfaction with the intervention.This complements Nilsen and Bernhardsson's [54] scoping review where authors found that the most extensively cited context dimensions included "organizational support, financial resources, social relations and support, and leadership" (p. 1).Current findings highlighted the need for a tailored recruitment strategy with language that is appealing to potential participants and getting 'buy in' and agreement with partner organisations in advance.Other participants noted that VR is helpful across education and in any context.
The current study contributes to advancing knowledge of online and VR interventions in a variety of settings [55][56][57].The fact that many participants found the intervention to be a "fun" way to learn, "engaging" and "interactive" with some seeking more interactivity fits with the Preconscious Awareness to Action Framework underpinning the E-MAT VR intervention [38,39] and the research team's efforts to create explicit memories which combine episodic memories (i.e., memorable events and activities such as VR gaming) with semantic memories that is general knowledge on health promotion.Ultimately, it is the research team's aspiration that men are facilitated to increase their conscious and unconscious awareness of testicular diseases through VR.
There is universal acceptance that health promotion is an effective tool for global health; however, there is less certainty on the tools and mechanisms of achieving this [58].VR offers great promise.However, the practicality of using VR as a health promoting tool for large numbers of participants was highlighted as a challenge.This could also be seen as a positive as VR offers the potential to ensure fairer access to and from hard-to-reach people and places [59].In addition, the constant evolution of technology creates additional challenges for researchers and clinicians in keeping interventions up to date [59].
Two key recommendations relating to E-MAT VR refinement were cited by study participants.Participants recommended enhancing the interactivity and visual content of the intervention.This desire for increased interactivity has been observed across other feasibility tests of web-based or digital interventions [60].Voorheis et al. also highlighted the importance of incorporating the Behavioral Design and Design Thinking theory into mobile health interventions enunciating the importance of incorporating user-centred features and behaviour change content [61].In addition, participants noted that the reach of the intervention may be improved by targeting male-specific environments.This complements men's mental health promotion interventions (n = 25 papers) which highlighted the importance of both workbased interventions and gender-sensitive interventions which together have the potential power of giving permission to other men "in norming conversations about ordinarily private health matters" (p.1834) [62].
Finally, the perceived effectiveness of intervention components, the feasibility of the study and intervention procedures, the relations between implementation, mechanisms, and context, and the barriers and facilitators were all examined in this evaluation.In terms of feasibility, participants felt that the intervention was suited to men from different ethnic backgrounds, although this was not explicitly tested, and participants were ethnically homogenous.Furthermore, participants were satisfied with the time taken to complete the intervention and the proportion of participants who participated as a percentage of those who registered interest to participate in the intervention was high (84%).Participants extolled the potential utility of VR as an educational tool in many contexts including schools and hospitals whilst also acknowledging that there may be limited contexts in which this type of intervention is applicable.Although a relatively new concept which requires further research [55], VR interventions may be an important means of meeting demand to increase health promoting activities when human resources are over-stretched.Furthermore, they provide an alternative opportunity in delivering health promoting information to hard-toreach populations [63,64].

Strengths, limitations, and lessons learned
The pilot feasibility study and mixed method approach to the process evaluation enhanced the data and enabled wider perspectives on the VR intervention to be appreciated.This was a pilot feasibility study with an embedded process evaluation which signposted the way for a future RCT.Modifications for both, intervention delivery and research processes were highlighted which will make a future RCT more likely to achieve its target recruitment and provide valuable research evidence that will facilitate actionable future recommendations for testicular selfexamination.
Our study, however, is not without limitations.Below is a list of lessons learned to address the limitations.While this list is not exhaustive, it is valuable for the scaling up of the interventions and the conduct of a future RCT.Lessons learned are also of relevance to researchers who are planning on testing the feasibility of complex technology-based health promoting interventions.
Lesson 1: Using virtual reality to promote the health of young men.The number of VR users is growing.The global VR market size is projected to increase from <12 billion U.S. dollars in 2022 to >22 billion U.S. dollars by 2025 [65].Advancements in VR have led to the development of user-friendly, lightweight, affordable, accessible, and wireless VR technology [42].Most VR users (94%) are aged 18 to 54 years, with the majority (60%) being men [66].Therefore, VR can serve as a tool to engage hard to reach populations (i.e., younger men) in health promotion initiatives.This could explain the high satisfaction and the high retention rate (89.2%) among our participants.Having said that, while testicular knowledge and testicular self-examination behaviour improved significantly among all participants, these outcomes did not differ significantly by trial arm.However, this was a feasibility trial and a full RCT, with a sample size powered to detect the efficacy of the intervention would be needed to establish efficacy.
Lesson 2: Estimating resources incurred by the interventions.Interactive digital interventions tend to outperform non-interactive ones [67].Such interventions, however, are expensive.Indeed, resources incurred in our study were identified by researchers as a potential challenge for a future RCT.Therefore, investigating the cost effectiveness of E-MAT VR versus E-MAT E is important to inform policy, resource allocation decisions, and the design and conduct of a future RCT.This would involve, for example, estimating intervention delivery costs inclusive of personnel and material, investigating healthcare utilisation regarding testicular disease at the conclusion of the RCT, and estimating participants' willingness to pay for E-MAT VR and E-MAT E .It is notable that VR as a medium is becoming much more mainstream with the target population more likely to own VR devices in the future which will help with costs [42,65,66].
Of note, a feasibility economic evaluation was conducted as part of our study to explore the practicality of conducting a full-scale economic evaluation in a future RCT.Results from the feasibility economic evaluation have been analysed but not published yet.Initial results, however, suggest that we proceed with an economic evaluation for a full RCT.
Lesson 3: Revisiting and refining the intervention.Some minor technical issues, with a very small number of participants, may have impacted their experience of the intervention.Therefore, there is value from revisiting E-MAT VR to help identify technical issues/glitches.
There is also value from incorporating more visual content, interactive elements, and gamification features to maximise engagement and potentially improve the effectiveness of E-MAT VR .
Lesson 4: Accounting for confounders.Given that the focus of our study was on process and feasibility rather than efficacy, we decided from the outset not to exclude participants who had a personal or family history of testicular disease.We do acknowledge, however, that such individuals may be more familiar with signs, symptoms, treatment, burden, and the overall experience of a patient with testicular disease.Furthermore, participants were GAA players and coaches who are more susceptible to testicular injuries and consequent disease.These individuals could also be more aware of testicular diseases.However, one could argue that given their susceptibility to the disease, the target population is appropriate.Nevertheless, these factors could have affected participants' knowledge at baseline.Notwithstanding this potential confounder, only 2 of the 74 participants reported a personal history of testicular disease.The inclusion of participants who have a personal and/or family history of testicular disease ought to be considered in the design of a future RCT.
Lesson 5: Ensuring diversity within the sample.The limited ethnic diversity within the sample may have limited our ability to assess the potential problems with the experience of the research process or the intervention in a more diverse sample.This arises from the relatively ethnically homogenous population in Ireland, though it is changing, and is particularly ethnically homogenous for indigenous sports like the GAA.Therefore, there is value from expanding the study population beyond the GAA, to include a more diverse sample of men as well as targeting more heterogenous male-dominated environments.
Lesson 6: Encouraging patient and public involvement.The importance of patient and public involvement in health research is widely recognised and advocated [68].The contribution of our public and patient representatives (AO'C, MO'R) was instrumental in ensuring that study documents were clear, and the study was relevant to younger men.In addition, both public and patient representatives played a key role in recruiting several participants from their GAA clubs.This strength ought to be leveraged while planning recruitment in a future RCT.
Lesson 7: Incentivising participants.As identified by participants and researchers, the provision of a conditional incentive at the conclusion of the study was one of the key contributors to the high retention rate.This warrants consideration in a future RCT.Of note, the model of payment that we used is an appreciation model offered to participants at the end of the study, therefore avoiding undue inducement [69].
Lesson 8: Examining survey length and content.Lengthy and repetitive surveys tend to lead to missing data, participant disengagement, and drop-out [70].Indeed, information overload and repetition within the surveys were identified as problematic by some of our participants and researchers, despite having a panel of patient and public representatives review the instruments a priori.To this end, there is value from carefully examining the survey length and content.This would help ensure optimal participant engagement and data collection in a future RCT.
Lesson 9: Using qualitative research.Qualitative research alongside RCTs provides added value [71,72].In our study, qualitative research, particularly in the process evaluation, helped provide an in-depth account of men's experiences of participating as well as researchers' experiences of delivering the interventions.Qualitative research also informed the lessons learnt which will be considered in the design and conduct of a future RCT.

Conclusion
Our study highlights the feasibility, context, fidelity, usability, and satisfaction associated with the implementation of a VR intervention in relation to testicular diseases among young athletes.The intervention has the potential to engage this audience in health education [23].Findings from our study are promising.Considering the lessons learned, some modifications are required to the E-MAT interventions prior to conducting a future definitive RCT comparing the effect of E-MAT VR to E-MAT E .Overall, this study has provided data which supports the potential utility of VR as an education and health promotion tool in a healthcare context for a hard-to-reach population.

Table 5 . Distribution of knowledge scores by trial arm and time point.
Treatment effect estimated using linear regression.Models for knowledge scores at T1 and T2 are adjusted for baseline knowledge scores.https://doi.org/10.1371/journal.pone.0307426.t005purposefully felt or examined their testes within the past three months.Additionally, in the past three months, 61.7% (n = 21) of E-MAT VR participants versus 71.9% (n = 23) of E-MAT E participants advised at least one man about the importance of feeling and examining their testes in the shower or bath at least once (OR 0.6, 95%CI 0.2 to 1.8, p = 0.39) (S6 Table in S3 File).The internal consistency of multi-time scales was generally high and in line with what has been previously reported (S7 Table in S3 File) ** Mean (SD)***